380 USES OF THE LIVER DUCTLESS GLANDS 



Fibrous Structure of the Spleen (Trabeculce). From the internal 

 face of the investing membrane of the spleen and from the fibrous 

 sheaths of the vessels (capsule of Malpighi) are bands, or trabeculae, 

 which, by their interlacement, divide the substance of the organ into 

 irregularly-shaped communicating cavities. These bands are 2 V to tV 

 of an inch (i to 1.7 millimeter) broad, and are composed, like the 

 proper coat, of ordinary fibrous tissue with elastic fibres and probably a 

 few non-striated muscular fibres. They pass off from the capsule of 

 Malpighi and the fibrous coat at right angles, soon branch, interlace and 

 unite with each other, becoming smaller and smaller, until they measure 

 5TTF to g 1 ^ of an inch (o. I to 0.42 millimeter). This fibrous network 

 serves as a support for the softer parts. 



Malpighian Bodies. These bodies are sometimes called splenic 

 corpuscles or glands. They are rounded or slightly ovoid, about -fa of 

 an inch (0.5 millimeter) in diameter, and are filled with what are 

 thought to be lymph-corpuscles, and free nuclei. The Malpighian 

 bodies have no investing membrane. With this difference, they resem- 

 ble in structure the solitary glands of the intestine. Both the cells and 

 the free nuclei of the splenic corpuscles bear a close resemblance to 

 cells and nuclei found in the spleen-pulp. The corpuscles are sur- 

 rounded with bloodvessels which send branches into the interior, to 

 form a delicate capillary plexus and with what is thought to be a 

 lymphatic space or sinus. 



The number of the Malpighian corpuscles in a spleen of ordinary 

 size has been estimated at about ten thousand. They are readily made 

 out in the ox and sheep, but frequently are not to be discovered in the 

 human subject. The occasional absence of these bodies constitutes 

 another point of resemblance to the solitary glands of the small intestine. 



The Malpighian bodies are attached to arteries measuring -fa to g 1 ^ 

 of an inch (0.32 to 0.42 millimeter) or less in diameter. They arc 

 often found in the notch formed by the branching of an artery, but they 

 usually lie by the sides of the vessel (see Plate IX, Fig. 3). 



Spleen-pulp. The spleen-pulp is a dark, reddish, semifluid sub- 

 stance, its color varying in intensity in different specimens. It is so 

 soft that it may be washed by a stream of water from a thin section, 

 and it readily decomposes, becoming then nearly liquid. It is contained 

 in the cavities bounded by the fibrous trabeculse, and it contains itself 

 microscopic bands of fibres arranged in the same way. It surrounds the 

 Malpighian bodies and contains the terminal branches of the blood- 

 vessels, nerves and lymphatics. On microscopical examination, it 

 presents free nuclei and cells like those described in the Malpighian 

 bodies; but the nuclei are here relatively much more abundant. In 



